In its broadest form, the present invention relates to folding equipment useful for folding inwardly the ends of a sleeve of overwrap material which surrounds a block or stack of material having a generally square or rectangular cross-section. In the preferred embodiment, the invention comprises a folder having a single, moveable element and three substantially stationary elements adapted to fold the end flaps of a sleeve of paper stock about a stack of pulp sheets. 2. Description of the Prior Art
For many years, and for many different applications, it has been necessary to wrap a box, block or stack of material to surround the top, bottom, sides and ends thereof with a suitable wrapping material. For example, in wrapping a sheet of paper about a stack of paper pulp, such as occurs prior to export of pulp, the package is inserted into an overwrap material in such a manner that a C-fold is formed. The ends are typically wrapped by folding the back, top and bottom portions thereof using pneumatic devices which extend toward a pulp bale and move in a defined path to press the overlying portions of wrap material against the block or stack. The stack, having a fold completed on two sides and an overwrap on three, is rotated so that the remaining open end having top, bottom, front and back flaps extends toward yet another pneumatic machine having many moving parts. The latter machine individually folds the four flaps around the remaining end using an engaging and pressing motion, after which the stack is moved to a strapping machine to secure the wrapping in place.
Such wrapping may be necessary thousands of times per day, and equipment which includes many moving parts is undesirable in such applications. Discussing the pulp process in somewhat greater detail, the pulp is typically prepared in sheet form and cut into equally sized rectangular sheets and stacked to a desired height. To increase the density to volume ratio, the stack is typically pressed and overwrapped by the process described above. The most complex, time consuming and expensive part of the process of preparing the pulp for shipment, after its preparation in the mill, is the folding of the ends of the paper sleeve, a process which is currently being performed by very complex and expensive machinery. Not only is the present equipment expensive, it is subject to mechanical failure resulting in numerous periods of plant down time. A folder which contains fewer moving parts and which would increase the speed of the packaging operation would represent a substantial advance in this art.